by Gideon Marcus

Last time, I talked about how America's space program has reached a level of reliability that you can…well…rely on!  Three days ago, at 1:05 PM EST, February 17, 1965, the eighth in the Ranger moon probe series took off successfully from Cape Kennedy.

Really, a Ranger has three launches.  First, the Atlas-Agena launched Rancher from the surface to a "parking orbit" 115 miles above the Earth.  Fourteen minutes after that, the Agena upper stage fired again for 90 seconds, changing Ranger's orbit such that its trajectory would intersect with the Moon.  Finally, the next day, Ranger executed a mid-course burn, firing its onboard engines for 59 seconds.  Now, instead of missing the Moon by 1,136 miles, it was set to hit Mare Tranquilitas at 4:57 AM EST, February 20.

That target, one of the darker areas of the Moon known as a "sea", was not easily decided upon.  Since Ranger 7 had impacted the Sea of Clouds, some scientists wanted Ranger 8 to hit a different kind of lunar terrain, perhaps the highlands further north.  Others were keen on exactly duplicating Ranger 7's mission so as to have two sets of data they could compare.  Ultimately, however, program manager George Mueller chose a target that would be support the Apollo mission — a flat area close to the equator.

Ranger 7 had started started its footage just ten minutes before impact.  Ranger 8, on the other hand, started shooting 23 minutes before the crash so that its first images would match the resolution that could be gotten from the best Earth-based cameras.  The moment of truth was a tense one — Ranger 6 had died right at the moment it turned on its TV cameras.

But Ranger 8 performed beautifully, taking a broader swath of photos than its predecessor and revealing an unprecedented wealth of information on the lunar surface before it kamikazed into the Sea of Tranquility at just under 6,000 mph.  Before its demise, it had returned 7,000 photos of the lunar surface.

At first blush, it doesn't look like we've learned much new.  The pictures Ranger 8 returned might well be swapped with those from Ranger 7 and none would be wiser.  On the other hand, it is nice to know that the Seas of the Moon are consistent.

What we still don't know is how safe the Moon is to land on.  Drs. Urey, Kuiper, and Whitaker all believe the lunar soil will hold a spacecraft, the latter two saying that the Ranger data say the Moon's dirt is something like crunchy snow in texture.  But it won't be until the soft-landing Surveyors start going to the Moon next year that we'll have real answers.

Originally, there were going to be up to seventeen Rangers.  However, the lack of success of earlier missions, and the fact that new spacecraft in the form of Lunar Orbiter and Surveyor will be online shortly, has reduced the remaining Ranger missions to just one.

As a result, it is likely that Ranger 9 will be given a more purely scientific mission, perhaps to some place no Apollo crew will visit.  Either way, given America's current track record, and that of Ranger, specifically, we can all hope it will be a crashing success!